The present invention generally relates to a catheter for insertion into a body for treatment thereof; and more particularly, to a catheter having a unique anchoring arrangement for releaseably anchoring the catheter at a desired treatment site in the body without the need for the catheter to be positioned in a vessel, body cavity or the like in order to facilitate the attachment of the catheter as well as to methods of utilizing the catheter.
One catheter having an anchoring arrangement for retention within the body is the Foley catheter. Commonly referred to as a balloon catheter, the Foley catheter has a balloon at its inner end which is inflated to wedge the catheter within an opening of the body, for example, the bladder. Disadvantages of the balloon catheter arrangement include the fact that the catheter must be positioned within a vessel or body cavity to provide a space in which the inflated balloon is held in order to facilitate attachment of the catheter. Further, the inflatable balloon, once inflated, does not always reliably deflate as required which can cause difficulties during removal as well as possible injury to the patient.
Alternative arrangements for anchoring medical devices within the body include the use of flexible feelers as disclosed by U.S. Pat. No. 3,467,090. These flexible feelers extent from a base into an end of a tube and project outwardly through openings in a sleeve at a substantial distance to positively engage with the cervical canal only when in the operating position.
A further catheter, also designed for positioning in a body cavity, such as, the bladder, is disclosed by U.S. Pat. No. 4,043,346 wherein an inner tubular member having a rounded expansion tip at its inner end is slidably mounted inside an outer tubular member. The rounded expansion tip of this catheter comprises a plurality of prongs biased outwardly and operable to expand and open when the prongs are pushed beyond an inner end of the outer tubular member. The prongs retract upon movement of the inner tubular member to a position where at least a portion of the prongs are within the outer tubular member.
While the above-noted anchoring arrangements are operationally quite efficient, none of these devices are adapted for precise positioning of a catheter at a desired location in the body without the requirement that the catheter be positioned within a body cavity in order to anchor the catheter. Since they engage and nest against the inner surface of the cavity, they do not stay firmly in place, especially for irregular surfaces. Moreover, the noted devices make no provision for using a catheter in the treatment of cancerous tumors wherein the catheter is inserted within the human body and left in place for several days to provide a sterile channel by which daily fractionation treatments to cancerous areas which can be conducted for up to several days at a time.
Oxygen therapy supplies oxygen through tubes from an external source to the pulmonary system. The tubes have included a nasal cannula and transtracheal tubes. To conserve oxygen, the exhalation portion of the cycle is sensed. The "Oxymizer" pendant senses the change in pressure mechanically to determine the exhalation portion. The "Oxymatic" is an electronic demand pulsed-oxygen delivery device. Generally pressure transducers have been used to determine the expiratory of the cycle. Depending upon the placement of the pressure transducer, the pressure may be altered by mouth breathing and other variables, thus there is a need for a sensing device which is not dependent on pressure to determine the expiratory portion of the cycle. These devices make no provision for using a catheter as a sensor for controlling the flow of transtracheal oxygen to the lungs so that oxygen is only delivered during the inspiratory phase of the respiratory cycle.
Accordingly, it is an object to the present invention to provide a catheter having a simple anchoring arrangement which permits attachment of a distal end of the catheter at a desired treatment site without the requirement to position the catheter within a body cavity to facilitate attachment.
A further object of the present invention is to provide a catheter having a simple anchoring arrangement which permits reliable removal of the catheter after completion of treatment.
It is yet another object of the present invention to provide a catheter and anchoring arrangement with a very small outside diameter so that the catheter can be introduced into the body within a needle and attached at areas inside the body which are accessible, without surgery, only by a needle.
It is also an object to the present invention to provide a catheter which forms a closed channel extending from a location outside of the body to a treatment site inside the body which prevents the introduction of foreign matter into the body that cause infection while still providing treatment access to the treatment site by means of a dedicated, sterile channel.
It is a further object of the present invention to provide a catheter which is adapted to be left in place at the desired location for several days to permit extended and/or multiple treatments of the treatment site, and can be reliably removed from the body on an out-patient basis without the need for surgery.
Still a further object of the present invention is to provide different methods of using the catheter to treat, for example, tumors, such as, deep dwelling tumors and the like, wherein the closed sterile channel, formed by the catheter, is employed to deliver treatment materials, such as, radioactive materials, to the distal end of the catheter positioned at the treatment site.
It is a further object of the present invention to provide a method of using the catheter to sense the inspiratory phase of a respiratory cycle to control the delivery of transtracheal oxygen to the lungs only during the inspiratory phase as well as a specialized configuration of the catheter for use as a sensor to control the flow of transtracheal oxygen to the lungs.
The unique catheter, according to advantageous embodiments of the present invention, permits treatment access to a wide variety of areas inside the body on an out-patient basis without the need for surgery. The catheter is typically provided with an overall diameter which permits insertion of the catheter into the body inside an opening of a flexible or rigid scope, for example, an endoscope or bronchoscope, to treat areas of the body which are accessible by such devices.
Further, due to its small diameter and at least the end being constructed of fluoroscopically opaque materials, that catheter can be placed into the body through a needle, so that, under a fluoroscope, the catheter is positioned anywhere in the body accessible by a needle to treat tumors or the like without the use of surgery.
Additionally, because the catheter is a closed system catheter, no foreign matter can enter the body through the catheter and cause infection which can occur during surgery.
Moreover, the catheter is provided with an unique anchoring arrangement which is simple, permits precise attachment of the distal end of the catheter at a treatment site without the need to position the catheter within a body cavity, and has a simple removal technique for reliably detaching the anchor for removal of the catheter.
Further, the catheter can be provided with a fail-safe removal arrangement which permits detachment of the anchor from the catheter to permit removal.
These and other objects and advantages are achieved according to preferred embodiment of the present invention by a catheter having an outer tubular member in which an inner tubular member is slidably disposed and spaced therefrom to form a storage space between the two members. An anchor for attaching the catheter at a treatment site is provided at a distal end of the catheter and is stored in the storage space between the inner and outer members.
The anchor comprises at least one, spring-loaded, hook-shaped arm which forms a barb when released from the storage space for penetrating surrounding tissue. The arm is attached at one end to the distal end of the inner tubular member and has a tissue penetrating end which is bent-back away from the distal end of the inner tubular member when the arm is deployed so as to firmly lodge into surrounding tissue. The arm is held in a stored, spring-loaded position at the storage space between the inner and outer members during insertion of the catheter into the body so as to be positioned substantially parallel to a longitudinal axis of the inner tubular member.
Relative slidable movement between the inner and outer member frees the tissue penetrating end of the spring-loaded arm from the storage space to permit the arm to swing out and away from the distal end of the inner tubular member and catch on tissue at the treatment site to anchor the catheter as desired. As the inner tubular member is pulled back, the bent-back tissue penetrating end of the anchor arm is driven into the surrounding tissue, much like a fish hook, to anchor the distal end of the catheter at a desired treatment site. The outer tubular member can then be completely removed from the inner tubular member and the body.
With a proximal end of the inner tubular member extending out of the body and the distal end closed, a closed channel is formed which terminates at the distal end of the inner tubular member positioned at the treatment site. The closed channel thus provides a sterile route by which treatment materials, for example radioactive materials, can be guided, in a dedicated manner, precisely and accurately to the treatment site.
To provide a simple catheter removal technique, a larger, outer sleeve or removal tube is inserted back over the inner tubular member and is pushed along the inner tubular member until this outer sleeve reaches the anchor. At this point, the inner tubular member is held stationary as the outer sleeve is advanced. This movement causes the arm of the anchor to bend in a backwards motion forcing the arm to withdrawn from and release its hold on the surrounding tissue. The spring-loaded arm of the anchor is then pulled back through the inside diameter of the outer sleeve so that it can no longer catch on the surrounding tissues and the entire catheter assembly is removed from the body.
According to another embodiment of the present invention, a second arrangement for detaching the anchor to permit removal of the catheter is provided wherein the anchor is releaseably connected to the distal end of the inner tubular member by a threaded arrangement. With a simple twisting of the inner tubular member, the threaded connection releases the anchor therefrom to permit removal of the catheter from the body. To maintain a closed system, the distal end of the inner tubular member is sealed upstream of the anchor. This arrangement is particularly useful when it is not possible to insert the outer sleeve back over the inner tubular member to remove the anchor from the body as discussed above. Further, since the anchor is preferably made of a stainless steel material, it does not interfere with body functions or cause any problems to the body when the anchor is left within the body.
According to yet a further embodiment of the present invention, the anchor comprises two bent-back, spring-loaded, stainless steel wire arms which each form a barb.
Methods of using the catheter to provide treatment inside the body include, but are not limited to, treatment of lung tissue, cervical tissue, pelvic tissue, interstitial, percutaneous type lesions, deep indwelling tumors, and the like.
A further and advantageous method of using a catheter which can be secured to an internal cavity without surgery includes the sensing of an inspiratory phase of the respiratory cycle to control the delivery of oxygen to the lungs only during the inspiratory phase. This arrangement is particularly advantageous in the controlled delivery of transtracheal oxygen which is administered to treat chronic respiratory insufficiency. Here, the distal end of the catheter is attached in a small peripheral bronchiole of the lung where it moves about 1 to 2 cm with each movement of the diaphragm during inhalation. By employing the movement of the distal end to trigger an electronic or mechanical switch which controls the operation of a flow valve, oxygen is delivered to the tracheal junction of the lungs only during the inspiration phase of the respiratory cycle. Although the securing device of the present invention is preferred, any device which will secure the catheter to the bronchiole can be used.
This control arrangement greatly reduces the loss of oxygen delivered to the lungs during the expiratory phase of the breathing cycle which is pushed out with expired carbon dioxide and wasted. Moreover, the transtracheal oxygen delivered by this method maintains the same blood level of oxygen with a much lower flow rate thereby reducing the amount of oxygen used as well as the cost of treatment.
These and other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.